英国牛津大学的科学家日前解开了一个困扰科学界达半个世纪之久的谜团：糖分子如何改变自己的形状及其背后存在的机理。
糖分子是世界上最丰富的有机分子，不仅在人类饮食中很常见，而且还能以纤维素和甲壳素的形式存在于植物和昆虫细胞中。早在1955年，科学家就从化学上确认了糖分子的变形现象，并将其命名为异头效应，不过他们认为这是因为有水或其他物质存在并产生影响的结果。
为了证实这个理论，在戴维斯教授和西蒙斯教授领导下，英国牛津大学两个团队的研究人员将糖气化，使之与其他所有物质分离，然后监测它们的表现。研究发现，分离出来的糖分子仍然保持着不寻常的化学外观。
戴维斯教授解释说：“异头效应是有机化学的基础，但是直到如今，我们对它的了解还非常有限。如果糖不能改变形状，那么我们的生活将完全不同，也许很多生物进程就再也不会起作用了。”
他还表示，糖很可能将成为制造业的未来，因为利用糖分子可以生产化学品，其可用性远远大于石油，而且人类也不太可能把地球上的糖耗尽。从理论上来说，化学家几乎可以将糖制成任何有机分子，因此人类应该可以利用糖去取代石油，并生产出需要利用石油生产的所有产品。
糖对医药的影响可能也同样巨大，人们对糖的了解远不及对DNA和蛋白质之类分子的了解。戴维斯教授指出：“将糖生物学转化为医学是生物学的最新前沿。但一旦能够达成，我们将获得巨大的回报。”（生物谷Bioon.com）
生物谷推荐原文出处：
Nature doi:10.1038/nature09693
Sensing the anomeric effect in a solvent-free environment
Emilio J. Cocinero,Pierre ?ar?abal,Timothy D. Vaden,John P. Simons& Benjamin G. Davis
The anomeric effect is a chemical phenomenon1, 2, 3, 4, 5, 6, 7, 8, 9 that refers to an observed stabilization10 of six-membered carbohydrate rings when they contain an electronegative substituent at the C1 position of the ring. This stereoelectronic effect influences the three-dimensional shapes of many biological molecules. It can be manifested not only in this classical manner involving interaction of the endocyclic oxygen atom (O5) found in such sugars with the C1 substituent (endo-anomeric effect) but also through a corresponding interaction of the electronegative exocyclic substituent with O5 (exo-anomeric effect). However, the underlying physical origin(s) of this phenomenon is still not clear1, 3, 4, 11, 12, 13, 14. Here we show, using a combination of laser spectroscopy and computational analysis, that a truncated peptide motif can engage the two anomers of an isolated sugar in the gas phase, an environment lacking extraneous factors which could confound the analysis. (Anomers are isomers that differ in the orientation of the substituent at C1.) Complexes formed between the peptide and the α- or β-anomers of d-galactose are nearly identical structurally; however, the strength of the polarization of their interactions with the peptide differs greatly. Natural bond order calculations support this observation, and together they reveal the dominance of the exo- over the endo-anomeric effect. As interactions between oxygen atoms at positions C1 and C2 (O1 and O2, respectively) on the pyranose ring can alter the exo/endo ratio of a carbohydrate, our results suggest that it will be important to re-evaluate the influence, and biological effects, of substituents at position C2 in sugars.
